Compacting device

ABSTRACT

A compacting device comprises an engine unit, a compacting unit having a tamping plate and a linkage mounting the engine unit on the tamping unit for reciprocatory movement of the tamping unit relative to the engine unit. Power is transmitted between the engine unit and the compacting unit by a transmission that includes an eccentric power output element driven by the engine unit and at least one, and preferably two, springs connected in tension between the compacting unit and the eccentric element of the power output. The linkage by which the engine unit is mounted on the tamping unit comprises two pairs of parallel links, the pairs being laterally spaced-apart and each link being pivotally connected at one end to the compacting unit and at the other end to the engine unit. A portion of a controlling handle is pivotably connected to the two links of each pair at pivot points intermediate the ends thereof, the pivot points being located on the links at points that have substantially no vertical reciprocatory motion in normal operation of the compactor.

United States Patent Grane et al.

[111 3,847,498 1 Nov. 12, 1974 COMPACTING DEVICE 221 Filed: Jan. 12, 1973 211 Appl. No: 323,210

[ 30] Foreign Application Priority Data Jan. 13, 1972 Sweden 346/72 [52] US. Cl. 404/133 [51] Int. Cl. E0lc 19/34 [58] Field of Search 404/133, 112

[56] References Cited UNITED STATES PATENTS 681,715 9/1901 Layne .1 404/133 3.109.354 11/1963 Van Kirk v l 404/133 3.308 728 3/1967 Brown l l 404/133 3,308,729 3/1967 Kestel 404/133 3.635.133 l/l972 Stougaard 404/133 Primary ExaminerNile C. Byers, Jr. Attorney, Agent, or FirmBrumbaugh, Graves, Donohue & Raymond [5 7 ABSTRACT A compacting device comprises an engine unit, a compacting unit having a tamping plate and a linkage mounting the engine unit on the tamping unit for reciprocatory movement of the tamping unit relative to the engine unit. Power is transmitted between the engine unit and the compacting unit by a transmission that includes an eccentric power output element driven by the engine unit and at least one, and prefer ably two, springs connected in tension between the compacting unit and the eccentric element of the power output. The linkage by which the engine unit is mounted on the tamping unit comprises two pairs of parallel links, the pairs being laterally spaced-apart and each link being pivotally connected at one end to the compacting unit and at the other end to the engine unit. A portion of a controlling handle is-pivotably connected to the two links of each pair at pivot points intermediate the ends thereof, the pivot points being located on the links at points that have substantially no vertical reciprocatory motion in normal operation of the compactor.

5 Claims, 1 Drawing Figure 7 COMPACTING DEVICE SUMMARY OF THE INVENTION The present invention relates to a compacting device of the type frequently called a soil tamper and which is employed in the compaction of soil or other earth materials, concrete, asphalt and the like. The compactor is manually controlled by operating handles and comprises an engine unit and a compaction unit that are mounted for relative reciprocatory motion by a mounting linkage system. The compaction unit has a tamping plate which is put in vibratory motion by a crank shaftdriven by the engine and a transmission connecting the compacting unit to the engine crank shaft.

More particularly, a compacting device, in accordance with the invention, includes an improved transmission between the engine unit and the compacting unit, the transmission including an eccentric power output element driven by the engine crank shaft and one or more springs connectedunder tension between the eccentric element and the compacting unit. In an exemplary embodiment, the eccentric element is a pin or stud mounted eccentrically on a power output shaft driven by the engine, and two springs connect the eccentric pin to the compacting unit, each of the two springs being journaled on the eccentric pin or stud at one end and being connected under tension to'locations in spaced relation to'the eccentric pin on a frame or housing that extends generally upwardly from the tamping plate.

The compacting device further includes a pair of handles, each of which is pivotably connected to the links of each of the pairs of links by which the engine unit is mounted on the compactingunit. The pivot points where the handles are connected to the respective links are located at locations on the links that are subject to substantially no reciprocatory movement in normal operation of the compactor.

Among the advantages provided by a compacting device of the present invention is a reduction in the height of the device, which is made possible by connecting the transmission springs directly between the compacting unit and the eccentric pin or stud-on the crank shaft. No intermediate connecting rod is employed. The connection of the handle tothe connecting links between the engine unit and the compacting unit at points that are subject to no substantial ancilliatory movement is highly advantageous in that it considerably reduces vibrations or oscillations in the handles and thereby makes it easier and less'strenuous to operate the device.

For a better understanding of the invention and the advantages it provides, reference may be made to the following description of an exemplary embodiment, taken in conjunction'with the accompanying drawing of the embodiment, which is a generally schematic side elevational view of the embodiment, a portion of the engine output shaft mounting and a'housing containing the transmission system being broken away for clearer illustration.

DESCRIPTION OF EXEMPLARY EMBODIMENT The embodiment of a compacting device, according to the invention, includes anengine 1 having a-generally downwardly extending housing 2 containing a power output transmission that includes an output shaft 4 journaled in bearings 3 in the housing. The output shaft 4 is provided with an eccentric stud or pin 5. The engine 1, frame 2 and output shaft 4 make up the engine unit of the compacting device, and that unit is connected by two pairs of links (links 7 and 8 on the near side in the drawing and similar links, which are not visible, on the far side) to a compacting unit that is composed of a generally vertical bracket or housing l0and a tamping plate 9 mounted on the lower end of the housing 10. The linkage by which the engine unit is connected to the compacting unit is described in greater detail below.

Reciprocatory motion of the compacting unit relative to the engine unit is provided by a transmission composed of two springs 11 and 12 mounted within'the casing 10 and substantially coaxially oriented relative to each other. One of the springs,'the lower onedesignated by the reference numeral 11 in the drawing, is secured at its lower end 13 to the bottom of the casing and at its upper end 14 to a holder 6 that is journaled on the eccentric pin or stud 5 on the output shaft 4. The other spring 12 is secured at its upper end 15 to the upper part of the housing 10 and at its lower end 16 to the holder 6. Both of the springs are connected under tension between the holder 6 and the housing 10; It will be observed in the drawing that the housing 10 extends upwardly a substantial distance above the output shaft 4, is located generally forwardly of the engine unit and receives the eccentric'pin 5 in a location substantially along the common axis of the two springs 11 and 12.

The two pairs'of links by which the engine'unit is mounted on the compacting unit straddle thehousing 2 associated with the engine unit andthe housing'l0 of the compacting unit.'(The two links'making up the second pair that are on the oppositeside' of the unit from that shown in the drawing are not visible in 'theldrawing.) The links of each pair are parallel to each other, and each is pivotably connected, at oneend at respective pivot points 17 and 18 to the housing 2 of the engine unit and at the other end to-the housing 10 of the compacting unit at pivot point 20 (the other pivot point not being shown in the drawing). A handle 24 by which the compacting unit is manually operated and controlled is pivotably connected at pivot points 22v and 23 to the respective links 7 and'8. A similar handle (not shown in the drawings).is pivotably connected at points corresponding to the points 22 and 23 associated with the other pair of links on the other side of the housing I 2. The location of the pivot points bywhich the handles are connected to the links is important and may be 'better understood in conjunction with the following'description of the manner in which the compacting device operates.

The engine 1 drives theoutput shaft 4 and produces eccentric orbital motion of the pin 5 on the output shaft about the axis of the shaft. Consequently, the springs 11 and 12 are alternately subjected to increases inthe tensile forces developed therein,-and such alternating increase in the tensile forcein each spring is transmitted to the housing 10 and, in turn, to the-tamping plate 9. Accordingly, the tamping plate is subject to. generally verticaltamping motion. More precisely, thecompacting unit oscillates vertically relative to the engine unit, but both the compacting unitand the engine unit actually oscillate vertically. Generally, the magnitude of vertical oscillatory motion of the engine unit is somewhat less than that of the compacting unit.

As a consequence of the relative vertical oscillatory movement between the engine unit and the compacting unit, the links 7 and 8 and the corresponding links on the other side of the unit which are not visible in the drawings pivot about the respective pivot points through an angle that is represented by angularly related lines designated by the letter A. In the design of a compacting unit constructed in accordance with the invention, it is possible to determine the location of points along the length of the respective links 7 and 8 that are not subject to any substantial vertical oscillatory motion (absolute motion) during normal operation of the compacting device. Putting it another way, there are points along the lengths of the links 7 and 8 that remain stationary in space during operation of the compacting device, the pivot points 17 and 18 moving upwardly and downwardly relative to the stationary point and the pivot point 20 and the corresponding pivot point (not shown) connecting the links and the housing of the compacting unit moving upwardly and downwardly some proportionate amount. In accordance with the invention, and as shown in the drawing, it is preferred that the pivot mountings 22 and 23 by which the handle is pivotably connected to the respective links be located at the point of zero oscillatory motion of the links.

It should be evident that the relative vertical oscilla tory motion of the engine unit relative to the compacting unit requires that an opening or hole 21 in the housing 10 be vertically elongated to afford vertical movement of the crank shaft 4 relative to the housing 10.

A compacting device constructed in accordance with the invention is free of any additional linkage between the output shaft 4 and the compacting unit other than the tensioned springs 11 and 12.:Moreover, the transmission system based on tensioned springs connected directly between a journaled holder on an eccentric pin driven by the output shaft eliminates any requirement for a sliding connection to accommodate the transverse motions involved in the orbital motion of the eccentric pin. All transverse motion is taken up by the flexibility and extensibility of the springs and by pivotal attachment of the upper end of the upper spring and the lower end of the lower spring to the housing. Consequently the tendency for lateral vibration to be imparted to the compacting unit is at a minimum. Further notable advantages are provided by the invention in that the handle is not subjected to any substantial vertical oscillatory motion, thereby making the compacting unit easier and less fatiguing to operate.

The above described embodiment of the invention is intended to be merely exemplary, and those skilled in the art will be able to make numerous variations and modifications of it without departing from the spirit and scope of the invention. All such variations and modifications are intended to be included within the scope of the invention as defined in the appended claims.

We claim: 1. A compacting device comprising: an engine unit having a power output shaft; a compacting unit including a tamping plate and a structural member affixed to the plate and extending in a generally upward direction from the plate;

mounting means for mounting the engine unit on the structural member of the compacting unit for oscillatory movement of the compacting unit relative to the engine unit, the engine unit being positioned by the mounting means such that the output shaft thereof is located intermediate the ends of the structural member and is oriented with its axis generally transverse to the structural member; and

power transmission means for transmitting power from the engine unit to the compacting unit to establish oscillatory movement of the compacting unit relative to the engine unit, the power transmission means including an eccentric pin connected to the power output shaft of the engine unit for rotation therewith and at least two springs, one end of each spring being pivotally connected directly to the eccentric pin and the other ends of the respective springs being connected under tension to points adjacent opposite ends of the structural member of the compacting unit.

2. An improvement according to claim 1 wherein the mounting means includes two pairs of links, the links of each pair being generally parallel and spaced generally vertically apart (considering the tamping plate as horizontal) and the pairs being spaced apart laterally,'each link being pivotally connected at one end to the compacting unit structural member and at the other end to the engine unit, and further comprising a handle unit having spaced elements pivotally coupled to all of the links at pivot points intermediate the pivotal connections to the engine unit and the compacting unit.

3. An improvement according to claim 2 wherein the pivot points between the handle and the links are at locations on the links having substantially no vertical reciprocatory motion in normal operation of the compac- I01.

4. An improvement according to claim 1 wherein the nature of the connection between the spring and the pin is exclusively rotary, whereby lateral movement of the spring is afforded by the flexibility of the spring it self.

5. An improvement according to claim 1 wherein the structural member of the compacting unit isa housing extending generally upwardly from the tamping plate, the housing including a portion disposed forwardly of the engine unit and a substantial distance above the output shaft of the engine unit, the output shaft extending into a space defined by the housing intermediate the ends thereof; and wherein the springs are enclosed within the housing.

l sm'ms 1r (5/69) FWE r QE-mmmi QREQ'HON Patent No. 3,847 ,498 zmea Nov. 12, 1974 (J Inventofls) Gunnar Grane et al It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

First page, following Item [76] insert:

-- [7 ign??? Dynapac Maskin Aktiebolag I Stockholm, Sweden Signed and sealed this 18th day of. February 1975.

(sEALl Attest:

. C. MARSHALL DANN RUTH C; MASON Commissioner of Patents Attesting Officer and Trademarks 

1. A compacting device comprising: an engine unit having a power output shaft; a compacting unit including a tamping plate and a structural member affixed to the plate and extending in a generally upward direction from the plate; mounting means for mounting the engine unit on the structural member of the compacting unit for oscillatory movement of the compacting unit relative to the engine unit, the engine unit being positioned by the mounting means such that the output shaft thereof is located intermediate the ends of the structural member and is oriented with its axis generaLly transverse to the structural member; and power transmission means for transmitting power from the engine unit to the compacting unit to establish oscillatory movement of the compacting unit relative to the engine unit, the power transmission means including an eccentric pin connected to the power output shaft of the engine unit for rotation therewith and at least two springs, one end of each spring being pivotally connected directly to the eccentric pin and the other ends of the respective springs being connected under tension to points adjacent opposite ends of the structural member of the compacting unit.
 2. An improvement according to claim 1 wherein the mounting means includes two pairs of links, the links of each pair being generally parallel and spaced generally vertically apart (considering the tamping plate as horizontal) and the pairs being spaced apart laterally, each link being pivotally connected at one end to the compacting unit structural member and at the other end to the engine unit, and further comprising a handle unit having spaced elements pivotally coupled to all of the links at pivot points intermediate the pivotal connections to the engine unit and the compacting unit.
 3. An improvement according to claim 2 wherein the pivot points between the handle and the links are at locations on the links having substantially no vertical reciprocatory motion in normal operation of the compactor.
 4. An improvement according to claim 1 wherein the nature of the connection between the spring and the pin is exclusively rotary, whereby lateral movement of the spring is afforded by the flexibility of the spring itself.
 5. An improvement according to claim 1 wherein the structural member of the compacting unit is a housing extending generally upwardly from the tamping plate, the housing including a portion disposed forwardly of the engine unit and a substantial distance above the output shaft of the engine unit, the output shaft extending into a space defined by the housing intermediate the ends thereof; and wherein the springs are enclosed within the housing. 